DETECTION OF PATHOGENIC AND NONPATHOGENIC BACTERIA BY MATRIX-ASSISTEDLASER DESORPTION IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY/

The proteins isolated from the whole cells of bacterial pathogens and related non-pathogenic simulants were analyzed directly, with minimal sample preparation by matrix-assisted laser desorption/ionization (MAL DI) time-of-flight mass spectrometry, Inspection of mass spectrometric profiles obtained from direct MALDI-MS analysis of the protein extrac ts revealed specific biomarkers for individual bacterial cells, The ob served biomarkers enabled us not only to detect pathogenic bacteria (B acillus anthracis, Yersinia pestis and Brucella melitensis), but also to distinguish them from the corresponding non-pathogenic species, By examining a series of strains of several Bacillus species (anthracis, thuringiensis, cereus and subtilis), it was possible to derive genus, species and strain-specific biomarkers from the measured molecular mas ses of the intact proteins, Additional series of biomarkers were obtai ned from direct mass spectrometric analysis of tryptic digests of the protein extracts. The application of this technique for rapid chemotax onomic classification of microorganisms is demonstrated.